/*
* Default text - jQuery plugin for html5 dragging files from desktop to browser
*
* Author: Weixi Yen
*
* Email: [Firstname][Lastname]@gmail.com
* 
* Copyright (c) 2010 Resopollution
* 
* Licensed under the MIT license:
*   http://www.opensource.org/licenses/mit-license.php
*
* Project home:
*   http://www.github.com/weixiyen/jquery-filedrop
*
* Version:  0.1.0
*
* Features:
*      Allows sending of extra parameters with file.
*      Works with Firefox 3.6+
*      Future-compliant with HTML5 spec (will work with Webkit browsers and IE9)
* Usage:
* 	See README at project homepage
*
*/
(function ($) {

    jQuery.event.props.push("dataTransfer");
    var opts = {},
		default_opts = {
		    url: '',
		    refresh: 1000,
		    paramname: 'userfile',
		    maxfiles: 25,
		    maxfilesize: 1, // MBs
		    data: {},
		    drop: empty,
		    dragEnter: empty,
		    dragOver: empty,
		    dragLeave: empty,
		    docEnter: empty,
		    docOver: empty,
		    docLeave: empty,
		    beforeEach: empty,
		    afterAll: empty,
		    rename: empty,
		    error: function (err, file, i) { alert(err); },
		    uploadStarted: empty,
		    uploadFinished: empty,
		    progressUpdated: empty,
		    speedUpdated: empty
		},
		errors = ["BrowserNotSupported", "TooManyFiles", "FileTooLarge"],
		doc_leave_timer,
		stop_loop = false,
		files_count = 0,
		files;

    $.fn.filedrop = function (options) {
        opts = $.extend({}, default_opts, options);

        this.bind('drop', drop).bind('dragenter', dragEnter).bind('dragover', dragOver).bind('dragleave', dragLeave);
        $(document).bind('drop', docDrop).bind('dragenter', docEnter).bind('dragover', docOver).bind('dragleave', docLeave);
    };

    function drop(e) {
        opts.drop(e);
        files = e.dataTransfer.files;
        if (files === null || files === undefined) {
            opts.error(errors[0]);
            return false;
        }

        files_count = files.length;
        upload();
        e.preventDefault();
        return false;
    }

    function getBuilder(filename, filedata, boundary) {
        var dashdash = '--',
			crlf = '\r\n',
			builder = '';

        $.each(opts.data, function (i, val) {
            if (typeof val === 'function') val = val();
            builder += dashdash;
            builder += boundary;
            builder += crlf;
            builder += 'Content-Disposition: form-data; name="' + i + '"';
            builder += crlf;
            builder += crlf;
            builder += val;
            builder += crlf;
        });

        builder += dashdash;
        builder += boundary;
        builder += crlf;
        builder += 'Content-Disposition: form-data; name="' + opts.paramname + '"';
        builder += '; filename="' + filename + '"';
        builder += crlf;

        builder += 'Content-Type: application/octet-stream';
        builder += crlf;
        builder += crlf;

        builder += filedata;
        builder += crlf;

        builder += dashdash;
        builder += boundary;
        builder += dashdash;
        builder += crlf;
        return builder;
    }

    function progress(e) {
        if (e.lengthComputable) {
            var percentage = Math.round((e.loaded * 100) / e.total);
            if (this.currentProgress != percentage) {

                this.currentProgress = percentage;
                opts.progressUpdated(this.index, this.file, this.currentProgress);

                var elapsed = new Date().getTime();
                var diffTime = elapsed - this.currentStart;
                if (diffTime >= opts.refresh) {
                    var diffData = e.loaded - this.startData;
                    var speed = diffData / diffTime; // KB per second
                    opts.speedUpdated(this.index, this.file, speed);
                    this.startData = e.loaded;
                    this.currentStart = elapsed;
                }
            }
        }
    }



    function upload() {
        stop_loop = false;
        if (!files) {
            opts.error(errors[0]);
            return false;
        }
        var filesDone = 0,
			filesRejected = 0;

        if (files_count > opts.maxfiles) {
            opts.error(errors[1]);
            return false;
        }

        for (var i = 0; i < files_count; i++) {
            if (stop_loop) return false;
            try {
                if (beforeEach(files[i]) != false) {
                    if (i === files_count) return;
                    var reader = new FileReader(),
						max_file_size = 1048576 * opts.maxfilesize;

                    reader.index = i;
                    if (files[i].size > max_file_size) {
                        opts.error(errors[2], files[i], i);
                        filesRejected++;
                        continue;
                    }

                    reader.onloadend = send;
                    reader.readAsBinaryString(files[i]);
                } else {
                    filesRejected++;
                }
            } catch (err) {
                opts.error(errors[0]);
                return false;
            }
        }

        function send(e) {
            // Sometimes the index is not attached to the
            // event object. Find it by size. Hack for sure.
            if (e.target.index == undefined) {
                e.target.index = getIndexBySize(e.total);
            }

            var xhr = new XMLHttpRequest(),
				upload = xhr.upload,
				file = files[e.target.index],
				index = e.target.index,
				start_time = new Date().getTime(),
				boundary = '------multipartformboundary' + (new Date).getTime(),
				builder;

            newName = rename(file.name);
            if (typeof newName === "string") {
                builder = getBuilder(newName, e.target.result, boundary);
            } else {
                builder = getBuilder(file.name, e.target.result, boundary);
            }

            upload.index = index;
            upload.file = file;
            upload.downloadStartTime = start_time;
            upload.currentStart = start_time;
            upload.currentProgress = 0;
            upload.startData = 0;
            upload.addEventListener("progress", progress, false);

            xhr.open("POST", opts.url, true);
            xhr.setRequestHeader('content-type', 'multipart/form-data; boundary='
			    + boundary);

            xhr.sendAsBinary(builder);

            opts.uploadStarted(index, file, files_count);

            xhr.onload = function () {
                if (xhr.responseText) {
                    var now = new Date().getTime(),
				    timeDiff = now - start_time,
				    result = opts.uploadFinished(index, file, jQuery.parseJSON(xhr.responseText), timeDiff);
                    filesDone++;
                    if (filesDone == files_count - filesRejected) {
                        afterAll();
                    }
                    if (result === false) stop_loop = true;
                }
            };
        }
    }

    function getIndexBySize(size) {
        for (var i = 0; i < files_count; i++) {
            if (files[i].size == size) {
                return i;
            }
        }

        return undefined;
    }

    function rename(name) {
        return opts.rename(name);
    }

    function beforeEach(file) {
        return opts.beforeEach(file);
    }

    function afterAll() {
        return opts.afterAll();
    }

    function dragEnter(e) {
        clearTimeout(doc_leave_timer);
        e.preventDefault();
        opts.dragEnter(e);
    }

    function dragOver(e) {
        clearTimeout(doc_leave_timer);
        e.preventDefault();
        opts.docOver(e);
        opts.dragOver(e);
    }

    function dragLeave(e) {
        clearTimeout(doc_leave_timer);
        opts.dragLeave(e);
        e.stopPropagation();
    }

    function docDrop(e) {
        e.preventDefault();
        opts.docLeave(e);
        return false;
    }

    function docEnter(e) {
        clearTimeout(doc_leave_timer);
        e.preventDefault();
        opts.docEnter(e);
        return false;
    }

    function docOver(e) {
        clearTimeout(doc_leave_timer);
        e.preventDefault();
        opts.docOver(e);
        return false;
    }

    function docLeave(e) {
        doc_leave_timer = setTimeout(function () {
            opts.docLeave(e);
        }, 200);
    }

    function empty() { }

    try {
        if (XMLHttpRequest.prototype.sendAsBinary) return;
        XMLHttpRequest.prototype.sendAsBinary = function (datastr) {
            function byteValue(x) {
                return x.charCodeAt(0) & 0xff;
            }
            var ords = Array.prototype.map.call(datastr, byteValue);
            var ui8a = new Uint8Array(ords);
            this.send(ui8a.buffer);
        }
    } catch (e) { }

})(jQuery);